Chipper Knives for Bruks, Vecoplan and Pallmann
Replacement knives and rotor blades for Scandinavian and German wood yards — Bruks drum chippers, Pallmann drum chippers and knife ring flakers, Vecoplan shredder rotors. These three names get ordered as if they were the same blade. They are not, and the difference is worth a paragraph each.
Bruks drum chippers
Bruks (Bruks Siwertell, Sweden) builds the drum chippers you find at the front of a sawmill line and in biomass terminals — logs and slabs in, screened chips out to the digester or the boiler. The knife is a long rectangular blade bolted through the drum, and the failure you actually see is not bluntness but edge chipping from tramp metal and rounded corners from running past the wear limit.
Three things have to match on a Bruks knife before anything else matters:
| What | Why it decides fit |
|---|---|
| Bolt pattern | Countersunk or through-bolted, and the spacing follows the drum generation. A knife of the correct length with the wrong hole pitch will not sit flush, and a proud knife corner is what breaks the anvil. |
| Knife thickness | Sets how far the edge stands out of the pocket. Too thick and the clearance to the anvil closes; too thin and the knife flexes under a slab. |
| Edge angle | Frozen softwood chips at 35–38°; hardwood and dirty bark at 40–42°. A shallow angle cuts freer and dulls faster — on a line running 24 h that is a knife change every shift. |
Vecoplan: rotor blades, not chipper knives
This is the mistake we see most. Vecoplan's VAZ single-shaft machines are shredders: a rotor carrying bolt-on blades that work against a counter knife and a screen. There is no bed knife and no drum. Ordering a “chipper knife” for a VAZ gets you a blade that is the wrong section, the wrong hardness and the wrong fixing.
Hardness is deliberately lower here than on a chipper: HRC 54–58 rather than 57–62. Shredder blades meet nails, hinges and stone; a harder blade chips where a softer one dents and can be dressed back. Selling HRC 62 into a shredder is a warranty claim waiting to happen.
Pallmann: drum chipper or knife ring flaker
Pallmann covers both, and they take different tooling. The PHT drum chipper takes a conventional long chipper knife against a bed knife. The knife ring flaker takes a ring of short flaker knives that slice across a rotating ring — a completely different blade, usually much shorter, with its own clamp and its own wear pattern.
| Machine type | Tooling | Typical failure | What we make |
|---|---|---|---|
| PHT drum chipper | Long chipper knife + bed knife | Corner rounding, tramp-metal chips | Knife to drawing, 6CrW2Si / 9CrSi, HRC 57–62 |
| Knife ring flaker | Short flaker knives in a ring | Uniform edge wear, thickness loss | Flaker knife to sample, wear-resistant grade |
For particleboard and MDF lines the flaker knife sets strand thickness, so the tolerance we grind to is the thickness of the knife body, not just the edge. Send the drawing and state the strand thickness you are targeting.
What to send for a quote
| Send this | Why |
|---|---|
| Machine make, model and drum/rotor generation | Bolt pitch changes between generations even when the length does not |
| Length × width × thickness in mm | Or a photo of the old blade with a ruler across it |
| Hole pattern photo, with a ruler in frame | Countersink angle and pitch are read off the photo |
| What you chip: logs, slabs, pallets, demolition wood | Decides hardness and edge angle; demolition wood needs the tougher grade |
| How often you change knives now | If it is weekly, the problem is often the anvil gap, not the steel |
Frequently asked
Can one knife fit a Bruks and a Morbark drum?
Rarely. Lengths sometimes come close; the bolt pitch almost never does, and the drum diameter sets how the knife sits. Measure the old blade and send the model — we match the fixing, not just the outline.
Do you supply the bed knife / anvil as well?
Yes. Chipper knives and bed knives should be replaced as a pair; a new knife against a worn anvil keeps the clearance open and gives you oversize chips no matter how sharp the knife is.
What is the usual lead time?
Stock sections in about 7 days; a new drawing 15–25 days after you approve it. One piece is enough to trial.
Related: Chipper knife overview · Morbark, Carthage & Precision Husky · Steel grades compared
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